[PATCH] fix endian problem in color_imageblit

Paul Mackerras (paulus@samba.org)
Thu, 12 Dec 2002 14:41:30 +1100


This patch fixes the endian problems in color_imageblit(). With this
patch, I get the penguin drawn properly on boot.

The main change is that on big-endian systems, when we load a pixel
from the source, we now shift it to the left-hand (most significant)
end of the word. With this change the rest of the logic is correct on
big-endian systems. This may not be the most efficient way to do
things but it is a simple change that works and avoids disturbing the
rest of the code.

Paul.

diff -urN linux-2.5/drivers/video/cfbimgblt.c pmac-2.5/drivers/video/cfbimgblt.c
--- linux-2.5/drivers/video/cfbimgblt.c 2002-12-10 15:20:32.000000000 +1100
+++ pmac-2.5/drivers/video/cfbimgblt.c 2002-12-12 09:14:47.000000000 +1100
@@ -103,10 +103,10 @@
{
/* Draw the penguin */
int i, n;
- unsigned long bitmask = SHIFT_LOW(~0UL, BITS_PER_LONG - p->var.bits_per_pixel);
+ int bpp = p->var.bits_per_pixel;
unsigned long *palette = (unsigned long *) p->pseudo_palette;
unsigned long *dst, *dst2, color = 0, val, shift;
- unsigned long null_bits = BITS_PER_LONG - p->var.bits_per_pixel;
+ unsigned long null_bits = BITS_PER_LONG - bpp;
u8 *src = image->data;

dst2 = (unsigned long *) dst1;
@@ -125,9 +125,10 @@
while (n--) {
if (p->fix.visual == FB_VISUAL_TRUECOLOR ||
p->fix.visual == FB_VISUAL_DIRECTCOLOR )
- color = palette[*src] & bitmask;
+ color = palette[*src];
else
- color = *src & bitmask;
+ color = *src;
+ color <<= LEFT_POS(bpp);
val |= SHIFT_HIGH(color, shift);
if (shift >= null_bits) {
FB_WRITEL(val, dst++);
@@ -136,7 +137,7 @@
else
val = SHIFT_LOW(color, BITS_PER_LONG - shift);
}
- shift += p->var.bits_per_pixel;
+ shift += bpp;
shift &= (BITS_PER_LONG - 1);
src++;
}
-
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